When you select the Beast Master Archetype (PHB, p. 93) at level 3, your companion gains the following benefits of your proficiency:

Add your proficiency bonus to the beast’s AC, attack rolls, and damage rolls, as well as to any saving throws and skills it is proficient in.

Does this mean that the DC 11 Strength saving throw of the wolf's Bite attack increases with the proficiency bonus of the Ranger? Or is the DC of the bite attack for the wolf not actually calculated, but determined as a set value?

1 Answer
1

No

Add your proficiency bonus to the beast’s AC, attack rolls, and damage rolls, as well as to any saving throws and skills it is proficient in.

A Wolf is proficient in Perception and Stealth, so you add your proficiency bonus to those. You increase the Wolf's AC of 13 by your proficiency, its +4 to attack rolls is increased, and you increase the bite attack's damage by your proficiency as well.

You do not actually increase any of the wolf's raw stats or their own proficiency bonus, so even if the ability was capable of scaling, you didn't actually change any of the properties it'd scale with.

The wolf still has the same ability scores and proficiency bonus as before.